Heat exchanger unit



Feb. 24, 1942. E. A. DEwALb HEAT EXCHANGER UNIT Filed Feb. 29, 1940 2 Sheets-Shed?l 1 lNvENroR EM e. www

Feb. 24, 1942.

E. A. DEWALD HEAT EXCHANGER UNIT Filed Feb. 29, 1940 2 sheets-sheet 2 INVENTOR M www mwmm ,www @mi ATTORNEYS Patented Feb. 24, 1942 'l HEAT EXCHANGE'R UNIT 4Edward A. Dewald, Massillon, Ohio, assgnor to The GriscomeRussell Company,

New York,

N. Y., a corporation of Delaware v Application February 29, 1940, Serial No.v321,364

e claims. (ci. ess-2o) This'invention relates to heat exchangers and `particularly to heat exchangers built up of units of the tube within tube type.

'The object of the invention is to provide a heatexchanger unit' having two closed iluid circulating channels, one enclosed by the other, whereby heat is transferred from one fluid to the other,'constructed so that the stress of differential expansion resulting' from' different teme' peratures of the two fluids is reduced to a minimum, so that the possibility of undetected cross leakage between the two iluids is eliminated and so that disassembly for clean-out purposes is easy. The advantage of this last characteristic is particularly apparentin the petroleum refining leld inwhich the uids circulated are generally of a dirty nature. Moreover, in this field temperatures and pressures used are constantly increasing making a combination of the advantages obtained by thisinvention highly desirable.

I propose to realize these objects and attain these advantages by an improved structure for the lloating head end of such heat exchangers.

I have illustrated my invention in two embodiments shown in the accompanying drawings in which:

Fig. 1 is anelevation partly in cross section of a heat exchanger unit embodying my invention;

Fig. 2 is a transverse section taken on the line 2-2 of Fig. l; and

Fig. 3 is an elevation partly in cross section of the floating. head end of a modied form of the embodiment shown in Fig. 1.

In the embodiment of the invention shown in Fig. 1, the fluid passage for one iluid is formed by the twin shell unitsgenerally designated I having a flanged inlet connection II and a anged outlet connection I2. Passage of the .fluid from the upper tube. I3 of the twin shell units I0 to the lower tub'e `I4 is secured b'y means of the connecting chamber I5 in the header I6.

The Walls of the chamber I5 are formed by the header I6 and the tube sheet 34 into which the upper tube I3 and lower tube I4 of the twin shell II) are sealed. The passage for the other circulating fluid is composed of the'tubes Il coaxially placed within tubes n extending within the twin Shen lo between the inlet and outlet connections II and I2 and the connecting chamber I5 they may be longitudinally iinned as shown at 2l to promote the rate of heat transmittal between the fluids in the concentric passages. e

The tubes I1 forming the inner uid passage are interconnected by the return bend 22. This return bend is U-shaped, has flanges 23 at both ends and expanded portions' 24 extending alongv its legs from the flanges 23. The purpose of the` expanded portion 24 is to. give expansion room to the lloating end 25 of the tubes I'I which ex-V tubes Il and the return bend 22 connecting them tend into the recesses in the header I6. 'I'he purpose of the lianges 23 is to provide keying means by which the thrust of the screw collar 26 may be employed to seat the return bend 22 rmly against the packing rings 21 which surround the tubes I'I in the recesses 20.

The operation of the screw collar 26 is thus to render leakproof` the sliding joint between the f 4and at the same time to seal off that sliding joint effectively from the connecting chamber I5 carrying lluid between opposite legs of the twin shell IIJ.

Tell-tale holes 28 are provided in the header I6 leading into the recesses 20 therein. 'Ihe packing rings 2l around the tubes II in the recesses 20 areiso arranged on either, side of a lantern ring 29 that it is positioned approximately directly under the tell-tale hole 2l.

Thus, when in operation, a heat exchanger embodying my invention cannot acquire undetected cross leaks Abetween the separate fluid passages since the only place where such a cross It is to be understood that the lower leg of the twin shell III` is identical in these respects to the upper leg thereof.

' In the modification of my invention illustrated in Fig. 3, the removable flanged header I6 shown in Figs. 1 and 2 has been eliminated and reinforcedtubular extensions 30 of the upper and lower legs of the twin shell I0 substituted there# for. separate on each leg of the twin shell I0, a substitute for the connecting chamber I5 found in the flanged header I6, shown in Figs. 1 and 2, has been provided by the interconnecting passage 3I.' The reinforced extensions 30 of the legs of the twin shell I0, as shown in Fig. 3, serveto Since these reinforced extensions 30 are' replace the recesses 20 in the flanged header I6. Since the extensions 30 have no bottom therein against which the packing rings 2l can be seated, the annular key 32 is provided, which slips around the tubes l1 and seats on the shoulder formed by the end of the legs of the twin shell Ill inside the extensions 30. In other respects the embodiment of my invention as shown in Fig. 3 does not diier from that shown in Fig. l.

' The construction of my invention entirely obviates expansion stress on the finned tube elements l1, by reason of the free sliding joint formed in the expanded portions 24 of the return bends 22, while the joint itself is so constructed that any cross leakage is instantly detected by drip through the telltale holes 28 and stopped by tightening the s crew collars 26. When inevitable fouling because of dirty circulating fluids makes cleaning necessary, instant and easy straight line access is provided to the tubes I1 simply by removing the return bends 22.

It is to be understood that my invention is not limited to the details of construction illustrated and described but includes all embodiments falling within the scope of the appended claims.

I claim:

1. A heat exchanger unit comprising a tube sheet, a pair of outer tubes affixed in said'tube sheet, an inner tube within each of said outer tubes and coaxial therewith, said inner tubes having floating ends, a header aixed to said tube sheet having a space forming a connecting chamber between said outer tubes, cylindrical recesses in the outer face of said header coaxial with said outer tubes and substantially greater in diameter than said inner tubes, said recesses'having apertures centered in their-bottoms through which the oating ends of said inner tubes protrude a substantial distance into the recesses, packing within the recesses and around the oating ends of the inner tubes, a U-tube having the legs thereof extending over the floating ends of the inner tubes, the diameter of the legs of the U-tube, where they extend over the oating ends of the inner tubes, being suciently greater than the diameter of. the floating ends of the inner tubes to permit free longitudinal movement of said floating ends, external anges on the ends of said legs, and screw collars around said legs threaded into the outer ends of said recesses and bearing on the flanges and compressing the packing.

2. A heat exchanger unit comprising a tube sheet, a pair of outer tubes ailixed in said tube sheet, an inner tube within each of said outer tubes and coaxial therewith, said inner tubes having oating ends, a header affixed to said tube sheet having a space forming a cannecting chamber between said outer tubes, cylindrical recesses in the outer face of said header coaxial with said outer tubes and substantially greater in diameter than said inner tubes, said recesses having apertures centered in their bottoms through which the floating ends of said inner tubes protrude a substantial distance into the recesses, packing within the recesses and around the floating ends of the inner tubes, lantern rings in said recesses around the floating ends of the inner tubes between layers of the packing, the header having apertures communicating with each of said recesses at the lantern rings, a U-tube having the legs thereof extending over` the floating ends of the inner tubes, the diameter of the legs of the U-tube, where they extend over the floating ends of the inner tubes, being sufciently greater than the diameter of the oating ends of the inner tubes to permit free longitudinal movement of said oating ends, external flanges on the ends of said legs, and screw collars around said legs threaded into the outer ends of said recesses and bearing on the flanges and compressing the packing.

3. In a heat exchanger unit of the type comprising a pair of outer tubes, an inner tube within each of said outer tubes and coaxial therewith and a header member mechanically connected to the end of each'of said outer tubes and having a cylindrical recess extending inwardly from its outer face coaxial with each of said inner tubes, which recesses have centrally apertured bottoms through which said inner tubes protrude a substantial distance into said recesses and have an inside diameter substantially greater than the outside diameter of said inner tubes, a U-tube of substantially the same diameter as said inner tubes having expanded legs tting over the ends of said inner tubes, external flanges on the ends of said legs of slightly less diameter than the inside diameter of said recesses, packing within said recesses and around said inner tubes, a lantern ring in each of said recesses and around each of said inner tubes between layers of said packing, said header member having apertures communicating with said recesses at said lantern rings, and screw collars around the legs of said U-tube threaded into the outer ends of each of said recesses and bearing on said anges and compressing the packing.

4. A heat exchanger unit comprising a tube sheet, a pair of outer tubes affixed within said tube sheet, an inner tube within each ofv said outer tubes and coaxial therewith, a header affixed to said tube sheet having a single large depression in the inner face thereof forming a connecting chamber between said outer tubes, said header member having a cylindrical recess extending inwardly from its outer face coaxial with each of said inner tubes, which recesses have centrally apertured bottoms through which said inner tubes protrude a substantial distance into said recesses and have an inside diameter substantially greater than the outside diameter of said inner tubes, packing within said recesses and around said inner tubes, a lantern ring in each of said recesses and around each of said inner tubes between layers of said packing, said header having apertures communicating' with each of said recesses at said lantern rings, a U-tube of substantially the same diameter as said inner tubes having expanded legs fitting over the ends of said inner tubes, external flanges on the ends tubes sealed around the outside thereof, an an nular member within each of said extensions abutting on the end of the outer tube therein, one of said inner tubes protruding snugly through each of said annular members a substantial distance into each of said extensions, a U-tube of substantially the same diameter as said inner said inner tubes, a lantern ring ineach of lsaid extensions and around each of said inner tubes between layers of said packing, said extensions having apertures communicating with the interior thereof at said lantern rings, and screw collars around the legs of said U-tube threaded into the outer ends of each of saidcylindrical-v extensions and bearing on said anges and compressing the packing.

6. In a heat-exchangerunit of the type comprising a pair of outer tubes, an inner tube within each of saidP outer tubes and coaxial therewith and a header member mechanically connected to the end of each of said outer tubes, said header member having a cylindrical recess extending inwardly from its outer face coaxial with ea'ch of said inner tubes, which recesses have centrally apertured bottoms through which :said inner tubes protrude a substantial distance into said recesses and have an inside diameter substantially greater than the outside diameter of said inner tubes, a U-tube having its legs tting over the ends of said inner tubes which protrude into said recesses, the portion of the legs which fit overl said ends of the inner tubes having an inside diametersufciently larger than the outside diameter of said ends of the inner tubes to permit free longitudinal movement of said ends of the inner tubes within the legs of the U-tube, key means on the ends of said legs of slightly less overall diameter than the inside diameter of said recesses, packing within said recesses around ,said inner tubes, a lantern ring in each of said recesses around each of said inner tubes between layers of said packing, said header members having apertures communicating with said recesses at said lantern rings, and screw collars around the legs of the U-tubes threaded into the outer ends of said recesses '\and bearing on lsaid key means and compressing the packing.

EDWARD A. nEWALD. 

